This study will be divided into three parts, conducted concurrently: Part one will be a study of the fundamental fracturing process of both glass and plastic ophthalmic lenses. This will include (a) making a mathematical model of the impact process considering the ball as rigid and the lens as an elastic brittle material, (b) calculating the stress distribution in the lens for various impact velocities, and (c) devising an experimental test to validate the model using strain gauges and high-speed photography. Such factors as lens shape, weight, dioptric power, curvature of the front surface as well as missile form, mass and velocity will be studied and their effects described mathematically, making use of conventional mathematical methods and formulae for analysis of shock wave propagation and Finite Element Analysis. Part two will be the establishment of norms for fracture or failure of ophthalmic lenses under a variety of stresses. Part three will be experimentation with various means for improving the fracture resistance of ophthalmic lenses that are delivered to the public. Fracture resistance may be improved by developing means of detecting inherent weaknesses so that these weak lenses may be eliminated or screened out early in the manufacturing process. It may be possible to improve fracture resistance by improving methods of surface preparation before heat treating (avoidance of sub-surface flaws created in the polishing process) or sealing these flaws by making flame polishing with hydrogen and possibly quenching in an atmosphere free of oxygen as an integral part of the heat treatment process.